The present invention relates generally to wireless communication systems, and in particular, to a wireless communication system that supports both full-duplex and half-duplex operation.
Multi-user, wireless packet data communication systems are known. These systems typically include full-duplex base radio sites operating in conjunction with a support infrastructure for providing interconnect, dispatch and/or Internet protocol (IP) services. The base radio sites are linked to a population of half-duplex and full-duplex mobile subscriber units by way of radio frequency (RF) communication channels.
Each base radio site controls one or more pairs of RF communication channels, where each channel pair supports mobile subscriber units (SUs). One channel of each pair is designated as an uplink channel for carrying information from the mobile subscriber unit to the base site, while the other channel is designated a downlink channel carrying information from the base site to the mobile subscriber unit. Full-duplexed base stations are capable of simultaneously transmitting on the downlink channel and receiving on the uplink channel. However, half-duplex subscriber units can only transmit or receive at any given time. Employing a combination of full-duplex base stations and half-duplex subscriber units in a system can lead to xe2x80x9ccollisionsxe2x80x9d on the RF link.
A xe2x80x9ccollisionxe2x80x9d occurs when a particular subscriber unit is transmitting a packet of data and a base station is simultaneously transmitting another packet to the same subscriber unit. When a collision occurs, at least one of the two transmitted packets will be lost. Thus, retransmission of the lost packet is sometimes required, reducing overall system throughput.
Accordingly, there is a need for a method and system that prevents the collision of transmitted packets in wireless communication systems that support both full-duplex and half-duplex units.